The KBASE study aims to recruit overall 650 individuals at baseline (350 cognitively normal, 140 mild cognitive impairment, and 90 Alzheimer`s disease dementia older adults, and 70 young cognitively normal individuals) in Seoul, Korea. We decided to include 70 young control subjects who are supposed to have no amyloid deposition in the brain. The aim is to separate the influences of normal and pathological brain aging, and this is one of the distinct characteristics of the KBASE cohort.

  • Cognitively Normal Young & Middle-aged Adults (CN-YM)

    Age 20-54 yrs

    Young & Middle-aged
  • Cognitively Normal Old-aged Adults (CN-Old)

    Age 55-90 yrs

  • Mild Cognitive Impairment (MCI)

    Age 55-90 yrs
    Amnestic MCI (NIA-AA, 2011)

  • Alzheimer`s disease dementia (AD dementia)

    Age 55-90 yrs
    CDR=0.5 or 1
    Dementia (DSM-IV)
    Probable AD dementia (NIA-AA, 2011)

Participants were recruited from 4 recruitment sites, consisting of 2 university hospital and 2 public center in Seoul, South Korea. Although participants were recruited from multiple sites, all baseline assessments were done in a single center, Seoul National University Hospital.


As of March 2017, in total, 758 individuals had volunteered for the assessment of eligibility for participation in the KBASE cohorts. Among them, 591 individuals (74 CN-YM, 291 CN-old, 139 MCI, 87 AD dementia) were included in the KBASE baseline cohort and 167 individuals were excluded.

Inclusion criteria

Cognitively normal young & middle-aged adults (CN-YM)

(a) age 20-54 years (inclusive)

(b) Clinical Dementia Rating (CDR) score of 0

(c) no diagnosis of MCI or dementia

Mild cognitive impairment (MCI)

(a) age 55-90 years (inclusive)

(b) CDR score of 0

(c) no diagnosis of MCI or dementia

Cognitively normal old-aged adults (CN-Old)

(a) age 55-90 years (inclusive)

(b) CDR score of 0

(c) no diagnosis of MCI or dementia

Mild cognitive impairment (MCI)

age 55-90 years (inclusive) who met the following inclusion criteria based on core clinical criteria for diagnosis of amnestic MCI according to the recommendations of the NIA-AA guidelines were included:

(a) memory complaint corroborated by self, an informant, or clinician

(b) objective memory impairment for age, education, and gender

(c) largely intact functional activities

(d) not demented

Global CDR score of MCI individuals was 0.5

Alzheimer`s disease dementia (AD dementia)

age 55-90 years (inclusive) who met the following inclusion criteria were recruited:

(a) criteria for dementia in accordance with the Diagnostic and Statistical Manual of Mental Disorders 4th Edition (DSM-IV-TR)

(b) the criteria for probable AD dementia in accordance with the NIA-AA guidelines

(c) a global CDR score of 0.5 or 1

Exclusion criteria

Exclusion criteria for all participants include:

(a) presence of major psychiatric illness
(a) (e.g., schizophrenia, bipolar disorder, major depressive disorder, alcohol/substance abuse or dependence, delirium)

(b) significant neurological or medical condition or comorbidities that could affect mental functioning

(c) contraindications for MRI scan (e.g. pacemaker, claustrophobia)

(d) illiteracy

(e) presence of significant visual/hearing difficulty, severe communication or behavioral problems that would make a clinical examination
(e) or brain scan difficult

(f) taking an investigational drug

(g) in pregnancy or breastfeeding